Yalgoo (Western Australia) – Nitrate
“Cue, Meekatharra, Mount Magnet, New Norcia, Sandstone, Wiluna and Yalgoo have been granted an exemption from compliance with the nitrate guideline by the Department of Health. The water supplied is harmless to adults and children over the age of 3 months of age. Carers of infants younger than three months should seek advice from the Community Health Nurse regarding the use of alternative water sources for the preparation of bottle feeds. The Water Corporation provides bottled water free of charge for this purpose.” Water Corporation WA 2004/5 Annual Water Quality Report
Nitrate: ADWG Guideline 50mg/L. Nitrate is the product of oxygenated nitrogen created from the breakdown of organic matter; lightning strikes; inorganic pesticides; or explosives. The Australian Drinking Water Guidelines recommend that nitrate levels between 50-100mg/L are a health consideration for infants less than three months, although levels up to 100mg/L can be safely consumed by adults. Mainly a problem in Northern Territory and some communities in Western Australia.
Yalgoo – Western Australia – Hardness
2007/08: Yalgoo (Western Australia) – Hardness 365mg/L (Highest Detection Only)
2008/09: Yalgoo (Western Australia) – Hardness 320mg/L (max), 175mg/L (mean)
2009/10: Yalgoo (Western Australia) – Hardness 320mg/L (max)
2010/11 Yalgoo (Western Australia) Hardness 340mg/L (max), 287mg/L (av)
2011/12 Yalgoo (Western Australia) Hardness 330mg/L (max), 323mg/L (av)
2013/14 Yalgoo (Western Australia) Hardness 350mg/L (max), 340mg/L (av)
2014/15 Yalgoo (Western Australia) Hardness 330mg/L (max), 330mg/L (mean)
2015/16 Yalgoo (Western Australia) Hardness 320mg/L (max), 310mg/L (mean)
“To minimise undesirable build‑up of scale in hot water systems, total hardness (as calcium
carbonate) in drinking water should not exceed 200 mg/L.
Hard water requires more soap than soft water to obtain a lather. It can also cause scale to form on hot water pipes and fittings. Hardness is caused primarily by the presence of calcium and magnesium ions, although other cations such as strontium, iron, manganese and barium can also contribute.”
Australian Drinking Water Guidelines 2011
Yalgoo – Western Australia – Total Dissolved Solids
2008/09: Yalgoo (Western Australia) – Total Dissolved Solids 980mg/L (max), 617mg/L (mean)
2009/10: Yalgoo (Western Australia) – Total Dissolved Solids 989mg/L (max)
2010/11 Yalgoo (Western Australia) Total Dissolved Solids 1069mg/L (max), 914mg/L (av)
2011/12 Yalgoo (Western Australia) Total Dissolved Solids 1052mg/L (max), 1040mg/L (av)
2013/14 Yalgoo (Western Australia) Total Dissolved Solids 1063mg/L (max), 1060mg/L (av)
2014/15 Yalgoo (Western Australia) Total Dissolved Solids 1064mg/L (max), 1038mg/L (mean)
2015/16 Yalgoo (Western Australia) Total Dissolved Solids 1018mg/L (max), 983mg/L (mean)
“No specific health guideline value is provided for total dissolved solids (TDS), as there are no
health effects directly attributable to TDS. However for good palatability total dissolved solids
in drinking water should not exceed 600 mg/L.
Total dissolved solids (TDS) consist of inorganic salts and small amounts of organic matter that are dissolved in water. Clay particles, colloidal iron and manganese oxides and silica, fine enough to pass through a 0.45 micron filter membrane can also contribute to total dissolved solids.
Yalgoo (Western Australia) – Chloride
2013/14 Yalgoo (Western Australia) Chloride 310mg/L (max), 305mg/L (av)
2014/15 Yalgoo (Western Australia) Chloride 320mg/L (max), 315mg/L (mean)
2015/16 Yalgoo (Western Australia) Chloride 300mg/L (max), 288mg/L (mean)
“Chloride is present in natural waters from the dissolution of salt deposits, and contamination from effluent disposal. Sodium chloride is widely used in the production of industrial chemicals such as caustic soda, chlorine, and sodium chlorite and hypochlorite. Potassium chloride is used in the production of fertilisers.
The taste threshold of chloride in water is dependent on the associated cation but is in the range 200–300 mg/L. The chloride content of water can affect corrosion of pipes and fittings. It can also affect the solubility of metal ions.
In surface water, the concentration of chloride is usually less than 100 mg/L and frequently below 10 mg/L. Groundwater can have higher concentrations, particularly if there is salt water intrusion.
Based on aesthetic considerations, the chloride concentration in drinking water should not exceed 250 mg/L.
No health-based guideline value is proposed for chloride.” 2011 Australian Drinking Water Guidelines
Yalgoo (Western Australia) – Silica
2013/14 Yalgoo (Western Australia) Silica 85mg/L (max), 83mg/L (av)
2014/15 Yalgoo (Western Australia) Silica 85mg/L (max), 66mg/L (mean)
2015/16 Yalgoo (Western Australia) Silica 85mg/L (max), 83mg/L (mean)
2016/17 Yalgoo (Western Australia) Silica 85mg/L (max), 77.5mg/L (av)
2017/18 Yalgoo (Western Australia) Silica 85mg/L (max), 85mg/L (av)
To minimise an undesirable scale build up on surfaces, silica (SiO2) within drinking waters should not exceed 80 mg/L.
Silica present in water is usually referred to as amorphous silica (i.e. lacking any crystalline structure). When silica is dissolved within water it forms monosilicic acid:
SiO2 + 2H2O à Si(OH)4
When the concentrations of monosilicic acid increase, polymerisation of the silica occurs, forming polysilicic acids followed by formation of colloidal silica. Monosilicic acid and polysilicic acids are the forms of silica analysed when determining dissolved silica content.
The deposition of silica from solutions can occur via various mechanisms. The deposition of silica that can cause the most problems for the water industry is via silica’s ability to deposit on solid surfaces that have hydroxyl (OH) groups present. Surfaces that commonly have hydroxyl groups present are glass and metallic surfaces. For example, dissolved silica will react with the surfaces of glass and begin to form a white precipitate. The silica forms silicates on the surface, resulting in silica build-up. In cases where customer complaints occur due to scale build-up, water hardness and silica concentrations should be investigated to determine the cause.
Silica can be a problem in water treatment due to its ability to cause fouling of reverse osmosis (RO) membranes (Sheikholeslami and Tan, 1999, Ning 2002, Sahachaiyunta and Sheikholeslami 2002). This occurs when the dissolved silica of the concentrate becomes super-saturated, causing silicates to form in the presence of metals, and these deposit on the membrane surface. The silicate then dehydrates, forming hard layers on the membrane that reduce the effectiveness of the process… 2011 ADWG
Frustration over poor water quality growing in WA regional communities
A number of regional communities across Western Australia have grown increasingly concerned their tap water is unsafe to drink and are becoming more reliant on bottled water.
The issue of poor water quality was first raised in State Parliament in 2000.
Twenty-six towns and communities were identified as not having acceptable drinking water, many of which are in the Mid-west and Goldfields regions.
Cue shire president Ross Pigdon, who has lived in the town all his life, said he had not drunk tap water for more than 15 years.
“Babies can’t drink it, pregnant women can’t drink it,” he said.
“I wouldn’t even use that water and boil the kettle and make a cup of coffee with it.
“I know for a fact it’s been going for 15 years. I think it’s about time they did something, 15 years is a long time.”
Mr Pigdon said the water also caused significant damage to infrastructure in the town due to scale build up, particularly in pipes, taps and air conditioning units.
Cue mother of three Caris Dorrizi said the water made her children sick and called on relevant authorities to fix the problem.
“When the kids drink it and they have it with cordial or something, they usually have diarrhoea,” she said.
“It’s not something to wait around for, we as a community here need something to be done.
Levels of minerals and impurities in the water in the 26 communities are up to 20 times higher than the state average.
In the 2015-16 financial year the average state-wide level of nitrate in drinking water was 5.98mg per litre, while the metropolitan average was 1.24mg per litre.
Of six samples taken during that time, Cue recorded average nitrate levels of 50.9mg per litre and a maximum of 53.1mg per litre.
Meanwhile, Yalgoo recorded an average of 75mg of nitrate per litre, with a maximum reading of 84mg per litre.
Bottled water trucked into communities
Shire of Yalgoo CEO Silvio Brenzi said the situation was not good enough.
“We need to keep asking questions of Water Corp as to why that quality of water is not at the level it should be,” he said.
“For individual residents who choose to drink bottled water, that cost is born by themselves, so it can be expensive.
“It is unfortunate that people are sort of driven to the point of having to purchase additional water.”
Each week the local shop owner of Yalgoo Raul Valanzuela sells 400 litres of water trucked in from Perth, to the community of 120 people.
He said the figure was twice as high in summer.
Since the Water Corporation was established in 1996, the Department of Health has provided it with an exemption from nitrate guidelines to 11 towns.
The Department of Housing provides bottled water to the other 15 communities.
As part of the exemptions the Water Corporation must provide bottled drinking water through nursing outposts for children under the age of three months.
According to Department of Health guidelines, an infant under the age of three months should not consume more than 50mg of nitrate per litre, while the rest of the population should not consume more than 100mg per litre.
Water safe to drink: Water Corporation
The Water Corporation said excluding the infants, the water in these communities was safe to drink.
But University of Western Australia environment engineer Professor Anas Ghadouani said there was not enough research on the impact of elevated nitrates.
“I think it is fair that the communities should be asking these questions about whether those guidelines may need to be reviewed or whether the quality of the water that is being provided at this very moment in time in 21st century Australia should be looked at carefully,” he said.
Of the 26 communities identified with water quality issues 16 years ago, only two have had water treatment facilities installed to deal with elevated nitrates and salts.
In 2007, two different types of water treatment facilities were trialled, an Electro Dialysis Reversal in Wiluna and a High Efficiency Reverse Osmosis plant in Yalgoo.
The trial of Yalgoo’s HERO plant was stopped just two years in, after it was revealed the plant had not made a significant difference to the town’s water supply.
While the plant was switched off in 2009, it was not decommissioned until earlier this year.
In its place the Water Corporation has installed an EDR facility, similar to that of Wiluna’s.
In an email between the Water Corporation and Yalgoo’s CEO Silvio Brenzi, the Corporation said the plant was switched on on August 22.
However, Water Corporation regional manager Steve Greeve conceded the plant was yet to begin operating reliably.
“It’s true, but it hasn’t been running reliably in that period and we’ve had it on and off as we’ve been calibrating, correcting and addressing issues that’s been arising during that commissioning phase,” he said.
“It’s probably a month or so before it will be running reliably.
No timeline for water quality improvement
Mr Greeve said Cue was the next town in line to receive a system to address water quality issues, but could not provide a timeline for when a solution for both Cue and other communities would be implemented.
He said each town had a different balance on chemicals or components in the water and each had to be assessed and treated individually.
Mr Ghadouani agreed that was the appropriate response, but said it could be done faster.